Method of making cap for paper core



June 17, 1969 p, s c m ET AL 3,449,817

METHOD OF MAKING CAP FOR PAPER CORE Filed Aug. 15, 1966 F 6 INVENTORS PHILIP S. CUSHING HARRIS E4 STONE ATTORNEYS BY mgwmq 0 m,

United States Patent Ofiice 3,449,817 Patented June 17, 1969 U.S. Cl. 29-41 4 Claims ABSTRACT OF THE DISCLOSURE A disk of steel is made into a cap for a paper core by two successive cold drawing steps which form a deep cup with a rim and also press a socket outward at the top of the cup. A substantial central portion of the bottom of the cup can be cut out. The cup can be made with a lower portion of reduced diameter to be cut away and then nested in the upper portion.

This application is a continuation-in-part of the U.S. application of Cushing and Stone, Ser. No. 331,860, filed Dec. 19, 1963 for Cap for Paper Core pursuant to which application Patent No. 3,291,413 was issued Dec. 13, 1966. The invention relates to a method of making a metal cap for tubular paper cores such as are used for rolls of newsprint and other kinds of paper. Newsprint for newspapers is customarily shipped in rolls weighing approximately a ton. These rolls are mounted in the printing presses which print the newspapers. For this purpose each roll is wound at the mill on a heavy tubular core of paper having a wall thickness of about /2 inch. The rolls are apt to be dropped or roughly handled in shipping, so to protect the ends of the cores from damage which would make it difficult to mount the roll, metal caps are provided on the ends of each paper core, each cap being made with a socket to receive a lug whereby the roll is keyed to the arbor or chuck to revolve therewith. As the cores are customarily shipped back to the paper mill for reuse, the caps serve to protect the ends of the cores for such reshipment. A considerable variety of caps for this purpose have been invented and patented. Those that have stood the test of time and are in actual use are rugged and expensive. It is an object of the present invention to provide a cap which is much less expensive to make but is satisfactory in use. It is a further object of the invention to provide a cap of sufiicient strength that can be made so inexpensively that it can be a throw-away item. Since this will obviate the necessity of reshipment to the paper mill, the paper core itself can be made more cheaply so that it also can be a throw-away item, thus saving the cost and trouble of reshipment after use as well as the incidental damage that often occurs in the course of reshipment.

As hereinafter described, the cap is made from a circular disk of sheet steel by drawing operations which result in a tubular cap which may have a reinforcing insert to fit tightly therein, the insert being cut from the cap after both have been simultaneously formed by the drawing operations.

For a more complete understanding of the invention, reference may be had to the following description thereof, and to the drawing, of which:

FIGURE 1 is a perspective view of the cap mounted on the end of a paper core;

FIGURE 2 is a perspective view of a circular disk from which the cap and insert are made;

FIGURE 3 is a sectional view, on a larger scale, of the cap and insert after the completion of the drawing operations but before the insert is cut from the cap;

FIGURE 4 is a sectional view of an end portion of a paper core in which a cap and insert have been mounted;

FIGURE 5 is a perspective view, on a reduced scale, of the cap alone; and,

FIGURE 6 is a perspective view of a step-product resulting from the first drawing operation.

In the following description of a method of making a cap, dimensions are given by way of illustration and not limitation for a cap to fit in a standard paper core having a three-inch inner diameter.

The starting piece is a steel disk 10 which is 5 /2 inches in diameter. This is subjected first to a cold drawing step by which the central portion 11 of the disk, having a diameter of 3", is depressed about reducing the diameter of the disk to about 4%". The resulting step product 13, illustrated in FIGURE 6, which is in the form of a shallow saucer with a plane rim 15 about wide, is subjected to a second drawing operation to deepen the central depression to a depth of 1%, forming a cylindrical cup 12 with a narrower rim. By this second operation also a socket 14 is pressed outward, some of the metal for this socket being drawn from adjacent portions of the rim 15 so that the rim 18 varies in extent from zero on either side of the socket to a maximum diametrically opposite to the socket. The bottom of the cup 12 or at least a substantial portion of it is cut out, this resulting in the cap shown in FIGURE 5. When the cap is inserted in the end of a paper core, spurs 34 may be punched in the cylindrical wall to project into the core wall so as to anchor the cap in place.

If a reinforcing insert 16 is desired to strengthen the cap, the starting piece 10 is a steel disk 6% in diameter. This disk is subjected to the two cold drawing steps hereinbefore described, the first step forming a shallow central depression 11 surrounded by a plane rim 15. The second operation deepens the depression into a cylindrical cup having a depth of about 2" and comprising two portions of different diameters, the lower portion '16 having a depth of about and an exterior diameter equal to the interior diameter of the upper portion 12 so that when the lower portion is cut oif it may be inserted in the upper portion to have a tight fit therein. The bottom 20 of the cup is punched to form a central hole 22, this hole as shown having a diameter of approximately an inch, and a die operates on the bottom of the cup to emboss thereon a circular rib 24 which surrounds the hole 22 and stiffens the bottom of the cup.

In the second drawing operation, as the cup is being formed, a socket 14 is pressed outward, the metal for the socket being drawn largely from the adjacent portion of the rim 15 so that the resulting rim 18 varies in extent from zero at the sides of the socket 14 to a maximum diametrically opposite the socket. By the second drawing operation also a radius 30 is formed at the juncture of the wall of the cup 12 and the flange 18. The lower portion 116 of the cup is severed from the upper portion 12 at the lower end 26 of the latter, this lower portion having a slight flare 28 at its upper end. This severed lower portion 16 is then inserted in the upper portion 12, the diameters of these members being such that the member 16 fits snugly in the member 12. The flared rim 28 of the insert nests in the radius 30 so that it is flush with the rim 18.

When a cap is put to use, it is pressed into an end of a paper core until the rim 18 bears against the end of the core and the socket 14 engages in a notch which has been cut in the end of the core. The hole in the bottom of the insert 16 reduces the weight of the insert and also provides for the entrance of a tool which may be used to extract the insert 16 from the tubular member 12 just before the paper roll which is wound on the core 32 is to be mounted on an arbor or chucks.

We claim;

1. A method of making a cap for a paper core having a notch cut in the end of said core, which comprises cold drawing a circular disk of sheet metal to form a shallow cup with cylindrical side walls and a wide plane rim, performing a second cold drawing operation on said cup to deepen said cylindrical cup and simultaneously to press a socket outward at the top of the cup, the metal for the socket being drawn from portions of said rim adjacent thereto whereby said plane rim is narrowed to vary from zero extent at the sides of said socket to a maximum diametrically opposite said socket, said socket being adapted to be assembled within said notch.

2. A method as described in claim 1, plus the step of cutting out at least a substantial portion of the bottom of said cup.

3. A method as described in claim 1, said second cold drawing operation forming said cup with an upper cylindrical portion and a shorter lower cylindrical portion having an exterior diameter equal to the interior diameter of said upper portion, cutting Off said lower portion and fitting it into said upper portion.

References Cited UNITED STATES PATENTS 2,016,225 10/1935 Bukolt 113121 2,157,978 5/ 193 9' Bullock 29-41 6 2,698,989 1/1955 Lyon 294l6 3,085,324 4/ 1963 Nelson 29416 THOMAS H. EAGER, Primary Examiner.

US. Cl. X.R. 113-116, 121 

